Carved in the Ice Wall, it says "Olaf Jansen was here"
ho ho -- love it - good olde Olaf ;-))
bare dry, profile may be like a wide Nepal / Tibet with entrance / exit for
hollow earth being covered up by map makers who want to remain alive.
not extremely deep but perhaps enough to put off curious folks ;-))
could be a bottomless trench - great cover up location.
also https://earthsky.org/earth/new-video-shows-life-in-the-deepest-ocean